The assembly file is attached but the part file (asm1_asm_1_AF0_ADM.SLDPRT) is not attached. We cannot run the study without it. Could you attach it?
I have attached all the files now and it should work. The original geometry is a box of aluminium with 10mm thickness. The geometry has been simplified with symmetry in 3 planes. There is an external pressure of 10 bar and internal pressure of 1 bar.
I haven't looked at your files, but you don't mention if you are doing a nonlinear buckling study. If not, then the Simulation linear buckling is unreliable in the non-euler range.
Your cube looks very strong, so maybe 600 is right.
1. Try to include some imperfection to the geometry or (and) to the load and I`m sure you`ll get smaller value.
2. Try to make nonlinear analysis + buckling after it (if it possible in SW simulation).
3. Try another quantity of elements through the thickness
4. Try another type of elements
And one more thing....create the whole box, don`t use one-eighth - you`ll lose some buckling modes in this case. remove internal pressure, apply only 9 of external
And one more thing Look at Abaqus - it is perfect! Super documentation, super solvers and super Python script for automation of repetitive tasks.
Thanks for the advise.